1. Field of the Invention
The present invention relates to a light source apparatus for emitting light.
2. Related Background Art
For example, a photolithography step in fabrication of semiconductor devices is carried out using a light source apparatus adapted to reflect ultraviolet (UV) light emitted from a light source such as a mercury xenon lamp, by a reflecting mirror and to output the reflected UV light, for exposure of a photoresist on a wafer. However, the light source apparatus of this type has the problem that extraneous matter such as sublimates produced during the exposure of the photoresist enters the light source apparatus, together with air introduced for air cooling of the interior of the light source apparatus from the outside, and reacts with the UV light to adhere to the reflecting surface of the reflecting mirror and others.
One of the well-known light source apparatus for solving this problem is the light source apparatus adapted to circulate air via a chemical filter and a cooler to the interior of the light source apparatus (e.g., cf. Japanese Patent Application Laid-open No. 9-106076). This light source apparatus is able to adequately cool the light source while preventing the extraneous matter from adhering to the reflecting surface of the reflecting mirror and others.